A steering system of a vehicle is a mechanism by which its driver controls the course of travel of the vehicle. The steering system comprises, in general, a steering control wheel, a steering shaft, a steering column and other related components that serve to transmit a driver's manipulation force upon the steering control wheel to a steering gear. The steering gear receives the manipulation force at a steering gear input, increases the magnitude of the force and transmits the amplified force to opposingly-oriented tie rods. The tie rods, in turn, transmit the manipulation force to a linkage mechanism coupled to steerable wheels of the vehicle. The steering gear typically includes a rack-and-pinion steering gear housed in a steering gear box, which is mounted to a support frame of the vehicle.
The general arrangement of a typical steering gear assembly 10 mounted to such a support frame is shown in FIG. 1. In this figure a pair of left- and right-hand longitudinal frame members 12, 14, respectively, are interconnected with a forward cross member 16 and a rear cross member 18, each cross member extending between the frame members. A steering gearbox 20 is mounted to an upper surface of rear cross member 18. A pair of opposingly-oriented tie rods 22 extend from steering gearbox 20. A base bracket 24, having a U-shaped portion that extends around steering gearbox 20, is coupled to rear cross member 18. An engine mount 26 is attached to base bracket 24. Finally, an engine mount bracket 28 is attached to engine mount 26.
A shortcoming of the aforementioned arrangement is that each component of the steering gear assembly must be separately manufactured and assembled. From the standpoint of the vehicle manufacturer each component has a number of cost elements associated with its purchase, distribution and warehousing. It is thus desirable to reduce these cost elements wherever possible by reducing the number of components in the assembly. Furthermore, the labor required to produce each part individually and then assemble them together adds to the overall cost of the steering gear assembly.
Another drawback of current steering gear assemblies is that their constituent parts must often be adapted to fit together, adding weight and further increasing component cost and assembly labor. For example, engine mount 26 of FIG. 1, which is ultimately coupled to rear cross member 18, requires the intermediary base bracket 24 extending between engine mount 26 and rear cross member 18 and shaped to fit around steering gearbox 20. It would be desirable to eliminate base bracket 24 and its associated cost elements and assembly labor.
The components of the steering gear assembly 10 of FIG. 1 must also be assembled in a particular order. Typically, rear cross member 18 is attached to frame members 12, 14. Steering gearbox 20 and tie rods 22 are then assembled to rear cross member 18. Finally, base bracket 24 is assembled to rear cross member 18, along with engine mount 26 and engine mount bracket 28. In the event that any maintenance to steering gear assembly 10 is required, it may be necessary to remove several of these components to gain access to a particular component to be serviced, adding to the maintenance cost of the vehicle. There is a need for a steering gear assembly that is less costly to produce, is easier to maintain, and is lightweight.